The present invention relates generally to a reaction member attachment system for use with a hydraulic, pneumatic, or other rotary fluid-operated wrench, and more particularly to such a system which is adapted for the assembly of large size tube fittings.
The petrochemical and other industrial process industries historically have relied upon threaded pipe and welded connections in the construction of fluid piping systems. More recently, however, large diameter tubing, i.e., 11/4-2 inch O.D., and associated tube fittings therefor in inch sizes 20, 24, and 32, and metric sizes 28 mm, 32 mm, and 38 mm, for example, have been suggested as a substitute in affording both faster and more reliable make-up without the need for welds and X-ray inspection, and in affording easier disassembly for line inspection, maintenance, and cleaning.
Other than being of a relative large size, the tube fittings of the type herein involved are well known as employed in a variety of installations to connect two or more runs of tubing, pipes, lines, or other conduits in fluid communication at a central junction. In basic construction, such fittings typically are formed from a metal such as copper, brass, steel, or stainless steel as a pressure vessel body having two or more branches or bosses for mechanical coupling to the ends of the tubes to be joined. Depending upon the number and relative orientations of the branches of the fitting, two port elbows and straights, and other configurations such as multi-port tees or crosses having three or more ports may be provided. The external surface of the body typically is configured as having hexagonal or other flats portions for engagement with a wrench or other tool during make-up or disassembly. Tube fittings of this type, which may be of a "flareless," ferruled variety, are manufactured by the Instrumentation Connectors Division of Parker-Hannifin Corp., Huntsville, Ala., under the tradenames A-Lok.RTM. and CPI.TM. Instrumentation Tube Fittings, and by the Crawford Fitting Co., Solon, Ohio, under the tradename "Swagelok.TM.."
A representative tube fitting of the above-described ferruled variety is described in commonly-assigned U.S. Pat. No. 3,499,671. As may be seen for the straight embodiment shown generally at 10 in FIG. 1, such fitting includes a body member, 12, having an internal central bore, 14, and an external surface, 16. Surface 16 is configured as having hexagonal flats for engagement with a wrench or other assembly tool. Bore 14, in turn, is configured to receive a distal end, 18, of a length of tubing, 20, at least partially therethrough as extending within body member 12 between a rearward port end, 22, and a forward internal shoulder, 24, thereof. Port end 22, which is externally-threaded, opens to receive the tubing distal end, and defines at that opening an internal circumferential sealing surface, 26, of a generally frustoconical or flared geometry. Shoulder 24, in turn, extends radially inwardly to provide a positive stop for the internal positioning of the tubing distal end within bore 14. In the representative configuration shown in the figure, fitting 10 has a forward port end, 27, which is tapered for a threaded pipe connection, but which alternatively may be configured for a second tubing connection.
For effecting a fluid-tight connection between the fitting body and the tubing, the tubing distal end 18 is received through a generally annular ferrule, 28, which is interposable coaxially between the fitting sealing surface 26 and the outer surface, 30, of the tubing distal end. In this regard, ferrule 28 includes a forward end, 30, and a rearward end, 32. The forward end 30 of ferrule 28 is configured as having a tapered outer surface for effecting a compressive, fluid-tight engagement with surface 26 of body member 12. In turn, the rearward end 32 of ferrule 28 is configured for an abutting engagement with radially-inward extending internal shoulder, 34, of an associated nut or other fastening member, 36, which likewise is received coaxially over the tubing distal end 22. As is shown, with ferrule 28 axially positioned between nut 36 and body member port end 22, and with tubing distal end 18 bottomed out on shoulder 34, nut 36 may be threadably rotatably engaged with the port end 22 of the body member urging the forward end 30 of the ferrule into an abutting, fluid-tight engagement with the sealing surface 26 of the body member. Moreover, as nut 36 is tightened onto port end 22, the forward end 30 of the ferrule is compressed radially inwardly to grippably retain the tubing distal end 18 and develops an additional sealing surface being developed therebetween.
Generally with respect to such tube fittings, sufficient torque must be applied to the nut to effect the compression of the ferrule necessary to develop a fluid-tight seal. Particularly with respect to large size fittings, this torque may be appreciable and difficult to develop by conventional methods. Heretofore, the state of the art in large size fitting assembly has involved the use of a pair of hand-operated wrenches of correspondingly large proportions. That is, in order to provide a lever arm capable of developing the necessary torque, the wrenches were extremely long and, necessarily, very heavy. Indeed, "cheater" bars often are used to extend the leverage of the wrenches. With one of these wrenches positioned and held manually by a technician on the body of the fitting to counteract the applied torque, another technician then had to position the other wrench on the nut for clockwise or counterclockwise rotation to effect its tightening or loosening. While the nut was being tightened, the rotations thereof typically were counted to assure that a proper connection was established.
It will be appreciated, however, that in the field, conditions may arise which limit access to the fitting. For example, adjacent runs of tubing may interfere with the positioning or rotation of the wrenches. With respect to tees and crosses, the access to the nut and fitting body is especially limited. Moreover, the technicians may be called on to operate the wrenches high above the ground or in other dangerous environments. Obviously, there is the constant potential for bodily injury should one of the wrenches slip. Given all these conditions, it sometimes occurs that the specified number of nut rotations could not be safely achieved. In such situations, the only recourse had been to operate the system at less than its specified fluid pressure and/or to endure some amount of leakage from the improperly made-up fitting.
With respect to bolt assembly application, such as in the tightening of pipe flange bolts, hydraulic and other fluid operated wrenches have been employed to alleviate the above-mentioned problems associated with hand wrenches. One such fluid wrench for turning threaded connectors is described in U.S. Pat. No. 4,825,730, reissued as Re. 33,951, as including a housing which accommodates a double-acting drive cylinder having an internal piston reciprocatingly movable therein under the action of a hydraulic or pneumatic fluid medium supplied by a separate pump for alternately extending and retracting an associated ram. The wrench further includes an engaging unit which is operably coupled with the ram and is powered under the control thereof for turning the threaded connector. The engaging unit includes a link having a central opening, and a toothed ratchet wheel which is rotatably received within the opening as configured to engage, for example, the hexagonal head of a bolt or nut. The link has an upper end which is pivotally connected with a free end of the ram by a connecting means such as a pin. A cooperating pawl is pivotally connected to the link such that when the link is rotated in a working direction by a power stroke of the ram, the pawl enmeshes with grooves of the teeth of the ratchet wheel to incrementally rotate the wheel with the link. However, when the link is rotated in an opposite direction by the return stroke of the ram, the pawl is configured to traverse over the ratchet wheel in a lost motion arrangement permitting the link to be repositioned for continued application of torque on the next power stroke of the ram.
The wrench also includes a reaction member which is attachable to the link via one or more pins. During the power stroke of the ram effecting the rotation of the link and ratchet in a first direction about an axis of rotation, a reaction force or moment is developed which tends to rotate the cylinder and housing in the opposite direction about the axis. The reaction member restrains the end of the cylinder opposite the ram in providing a reaction surface for bearing contact with a fixed object adjacent the bolt to be tightened or loosened. Depending upon the geometry of and available clearance in the bolt tightening application for which the wrench is intended, the reaction member may be configured as a pad or as an elongate lever for contact with the adjacent object.
For example, U.S. Pat. No. 4,706,527 discloses a reaction member which comprises a splined annular portion which is configured to adjustably engage the splines of a reaction support portion of a housing. A second portion of the reaction member is integrally formed with the first portion as extending laterally therefrom in the direction of the axis of the ratchet to abut, for example, the outer surface of a flange in which a threaded connector is provided. The reaction member thus is adjustable to any desired position depending up the direction of the reaction force.
U.S. Pat. No. 4,794,825 similarly discloses a reaction arm member which is removably connectable to the wrench housing in a multiplicity of rotational orientations relative thereto. The reaction arm member comprises an internally-splined, annular body portion and an integral L-shaped reaction arm which projects transversely from the body portion. For the adjustable, coaxial mounting of the reaction arm member thereto, the wrench housing includes a cylindrical rear portion which is formed as having a plurality of circumferential, axially extending grooves. Each of these grooves is configured to received a corresponding spline of the reaction arm member providing an interlocking engagement between the reaction arm member and the housing.
U.S. Pat. No. 5,142,951 discloses a reaction member which is rotatably positionable about an axis which extends parallel to the drive axis of the wrench. The member includes a pair of elongate support arms which extend from a cylindrical socket portion. The support arms are pivotally attached to a body portion of the wrench such that the socket portion is rotatably positionable for engagement with a bolt or other fixed adjacent to the bolt be tightened or loosened.
U.S. Pat. No. 4,385,533 discloses a reaction plate assembly for use in a hydraulic torque wrench. The assembly includes a generally flat, triangular plate which is attached to one end of the drive cylinder opposite the wrench socket. The plate is provided as having a perimeter section which is formed with a series of spaced-apart clevis bolt opening, and as having a perpendicular section which is formed with at least one ring bolt opening. The clevis section is positionably attachable to the cylinder end, with the nut ring of the other section being receivable over a nut located adjacent to the nut that is to be tightened or loosened.
U.S. Pat. No. 4,406,187 discloses an anchoring mechanism for preventing the counter-rotation of a motor driven wrench in reaction to the torque produced by the turning of a tool member. The anchoring mechanism has a plurality of tandemly-hinged members. One end of the members is attachable to the wrench, with the other end of the member being securable to a fixed reference base.
U.S. Pat. No. 4,106,371 discloses a power wrench tool for tightening a bolt, nut, or the like having an anti-reaction member for preventing the rotation of the tool due to reaction force. The anti-reaction member is configured to engage an adjacent nut.
In the operation of the representative fluid wrench described in U.S. Pat. Nos. 4,825,730 and Re. 33,951, the ratchet is engaged with the threaded connector to be turned, and the reaction member is abutted against an adjacent object. On the power stroke, working fluid pressure is admitted into one end of the cylinder via an associated supply line to displace the piston and thereby extend the ram. Responsive to the extension of the ram, the link is rotated a fixed angular displacement in a clockwise or counterclockwise direction, with the pawl and the ratchet enmeshed therewith being turned incrementally with the link. On the return stroke, fluid is admitted into the other end of the cylinder via a corresponding supply line to retract the ram and rotate the link in a reverse direction. The ratchet wheel, however, is made to remain stationary as the pawl is provided to slip over the teeth of the ratchet.
Other fluid operated wrenches which operate in a manner similar to that just described are shown in U.S. Pat. Nos. 5,398,574; 5,369,867; 5,357,828; 5,301,574; 5,203,238; 5,142,951; 5,140,874; 4,916,986; 4,794,825; 4,748,873; 4,706,526; 4,706,527; 4,480,510; 4,432,256; 4,429,597; 4,409,865; 4,309,923; 4,200,011; 4,086,830; and 3,706,244. Fluid operated wrenches are manufactured commercially by the Hytorc Division of Unex Corp., Mahwah, N.J., and by Sweeney Co., Englewood, Calif.
One such other wrench incorporates a hinged ratchet link assembly or head for greater accessibility to the workpiece. As is shown generally at 40 in the somewhat simplified, exploded view of FIG. 2, such head, which is marketed commercially by Hytorc under the name "Swing-Link.TM.," includes a housing, 42, which accommodates a drive cylinder, 44, having an internal piston (not shown). As before, the piston is reciprocatingly movable within cylinder 44 under the action of a hydraulic or pneumatic fluid medium supplied via one or more hoses or other conduits, one of which is referenced at 46, by a separate pump (not shown) for alternately extending and retracting an associated ram which is hidden in the view shown. Wrench 40 further includes an link assembly, shown generally at 48, which is operably couplable with the ram and is powered under the control thereof for the application of torque to a threaded connector or other workpiece. As may be seen with additional reference to the cross-sectional view of FIG. 3, link assembly includes a body portion, 50, which may be of a parallel plate construction, and a swing arm portion, 54, which depends from the body portion. Body portion 50 includes an attachment end, which is shown at 56 to be configured for a pivotable connection with a corresponding mount portion of housing 42 as having an upper slot or rebate, 58, receivable on a transversely-disposed pin, 60, of the housing, and a lower aperture, 62, configured for a straddling pin-mount registration with a depending boss, 64, of the housing.
Swing arm 54 is hingably coupled via pin 68 to one end of body portion 50. A split inner carrier, 70, adapted to be rotatably received within swing arm 54, is similarly hinged via pin 72 to be openable for accessing the workpiece. When closed (FIG. 4), carrier 70 defines with body portion 50 a central opening, 74, of the link for rotatably supporting an annular ratchet wheel insert, 75a-b. As is shown, ratchet wheel 75 also may be of a split, two-piece construction, each piece having a toothed outer circumference, 76a-b, configured for engagement with a cooperating pawl assembly of the carrier, and an inner circumference, 78a-b, with defines with the other piece a hexagonal-shaped opening, 80, configured to receive a correspondingly-shaped connector or other workpiece in a torque transmitting engagement therewith.
Looking additionally to FIG. 4, as is shown in phantom at 70', carrier 70 is rotatable within opening 74 along a plurality of bearings, one of which is referenced at 90, which are received within an arc-shaped raceway, 92. Carrier 70 includes a connecting portion, 94, configured for an operable coupling with the with piston ram. In this regard, the carrier is actuable by a power and return stroke of the cylinder for a reciprocating rotation about a central axis of rotation, referenced at 95, which corresponds to the axis of rotation of the subject workpiece. One or more spring-loaded pawls, two of which are referenced at 96a-b, are associated with carrier 70 for rotation therewith as configured to drivably engage the toothed outer circumference 76 of ratchet wheel 75. On the power stroke of the cylinder, the pawls thereby urge ratchet wheel 75 to rotate about the axis 95 in the torque-developing direction shown at 97. Depending on the size of the fastener, torques of about 100-1200 ft-lb, or more, may be developed for application to the fastener. On the return stroke of the cylinder, which need develop a torque of only about 1-2 ft-lb to rotate the carrier, the pawls are biased to traverse over the ratchet wheel to allow the repositioning of the carrier for the application of torque on the next power stroke of the cylinder.
In use, with ratchet wheel 75 positioned to engage the connector, carrier 70 and then swing arm 54 each may be clamped and secured around the wheel and with one or more fastening members, such as the cap screws pictured at 98a-b. Thereupon, on the power stroke of the cylinder, the ratchet wheel is rotated by the carrier to apply the developed torque to the fastener. Responsive to the applied torque, the fastener turns with the wheel in a first direction about the axis of rotation. By reversing the clamping of the wrench around the wheel, the direction of the applied torque may be changed to effect the rotation of the fastener in an opposite second direction about the axis. In this way, the fastener may be either tightened or loosened. It will be appreciated that wrench 40 is particularly adapted for applications wherein the connector to be rotated cannot be accessed from a distal or free end of the connector.
Although fluid operated wrenches, such as the above-described "Swing-Link.TM." wrench, have represented an advancement in the assembly of threaded connectors such as flange bolts, these wrenches have yet to be accepted for large size tubing fitting assembly applications. In this regard, tube fittings present unique geometric constraints which heretofore have frustrated the use of these wrenches. For example, in the make-up of multiport fittings such as tees and crosses, minimal opportunities are presented for access to the body of the fitting. Of course, if the fitting body is not immobilize as the nut is rotated, the body itself will have a tendency to rotate in the direction of the applied torque. Even with respect to the make-up of straight tube fitting, such fittings have geometries which are not amenable to access with the reaction members heretofore known in the art.
As the use of large diameter tubing in chemical process and other fluid transfer applications continues to increase, it will be appreciated that improvements in the assembly of large size fittings therefor would be well-received by industry. Preferred improvements would speed and simplify assembly, while minimizing the potential for leaks and injury to personnel.